ACT4523 Rev 5, 14-Nov-12 Wide-Input Sensorless CC/CV Step-Down DC/DC Converter FEATURES APPLICATIONS • • • • • • Car Charger/ Adaptor • Rechargeable Portable Devices • General-Purpose CC/CV Supply 40V Input Voltage Surge 38V Steady State Operation Up to 3A output current Output Voltage up to 12V Patent Pending Active CC Sensorless Constant Current Control − Integrated Current Control Improves Efficiency, Lowers Cost, and Reduces Component Count • Resistor Programmable GENERAL DESCRIPTION ACT4523 is a wide input voltage, high efficiency Active CC step-down DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. ACT4523 provides up to 3A output current at 225kHz switching frequency. − Current Limit from 1.5A to 3A − Patented Cable Compensation from 0Ω to Active CC is a patent-pending control scheme to achieve highest accuracy sensorless constant current control. Active CC eliminates the expensive, high accuracy current sense resistor, making it ideal for battery charging applications and adaptors with accurate current limit. The ACT4523 achieves higher efficiency than traditional constant current switching regulators by eliminating its associated power loss. 0.3Ω • ±7.5% CC Accuracy − Compensation of Input /Output Voltage Change − Temperature Compensation − Independent of inductance and Inductor DCR • • • • 2% Feedback Voltage Accuracy Up to 94% Efficiency 225kHz Switching Frequency Eases EMI Design Advanced Feature Set − Integrated Soft Start − Thermal Shutdown − Secondary Cycle-by-Cycle Current Limit − Protection Against Shorted ISET Pin • SOP-8EP Package Protection features include cycle-by-cycle current limit, thermal shutdown, and frequency foldback at short circuit. The devices are available in a SOP8EP package and require very few external devices for operation. CC/CV Curve HSB SW ACT4523 ENABLE EN ISET C1 47µF 5V FB GND COMP C2 R1 11.5k 2.2nF R2 52k R4 10k D1 SK34 VIN = 24V 5.0 L1 30µH Output Voltage (V) IN 6.0 C4 220µF R3 8.2k 4.0 ACT4523-001 Input 10V to 40V C3 22nF 50V VIN = 12V 3.0 2.0 1.0 0.0 0 0.4 0.8 1.2 1.6 2.4 2.0 2.8 3.2 Output Current (A) Innovative PowerTM -1- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 ORDERING INFORMATION PART NUMBER OPERATION TEMPERATURE RANGE ACT4523YH-T -40°C to 85°C PACKAGE PINS PACKING SOP-8EP 8 TAPE & REEL PIN CONFIGURATION PIN DESCRIPTIONS PIN NAME DESCRIPTION 1 HSB High Side Bias Pin. This provides power to the internal high-side MOSFET gate driver. Connect a 22nF capacitor from HSB pin to SW pin. 2 IN Power Supply Input. Bypass this pin with a 10µF ceramic capacitor to GND, placed as close to the IC as possible. 3 SW 4 GND Ground. Connect this pin to a large PCB copper area for best heat dissipation. Return FB, COMP, and ISET to this GND, and connect this GND to power GND at a single point for best noise immunity. 5 FB Feedback Input. The voltage at this pin is regulated to 0.808V. Connect to the resistor divider between output and GND to set the output voltage. 6 COMP 7 EN 8 ISET Output Current Setting Pin. Connect a resistor from ISET to GND to program the output current. Exposed Pad Heat Dissipation Pad. Connect this exposed pad to large ground copper area with copper and vias. Innovative PowerTM Power Switching Output to External Inductor. Error Amplifier Output. This pin is used to compensate the converter. Enable Input. EN is pulled up to 5V with a 4μA current, and contains a precise 1.6V logic threshold. Drive this pin to a logic-high or leave unconnected to enable the IC. Drive to a logic-low to disable the IC and enter shutdown mode. -2- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 ABSOLUTE MAXIMUM RATINGSc PARAMETER VALUE UNIT -0.3 to 40 V SW to GND -1 to VIN + 1 V HSB to GND VSW - 0.3 to VSW + 7 V -0.3 to + 6 V 46 °C/W Operating Junction Temperature -40 to 150 °C Storage Junction Temperature -55 to 150 °C 300 °C IN to GND FB, EN, ISET, COMP to GND Junction to Ambient Thermal Resistance Lead Temperature (Soldering 10 sec.) c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability. Innovative PowerTM -3- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 ELECTRICAL CHARACTERISTICS (VIN = 20V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS Input Voltage MIN TYP 10 Input Voltage Surge MAX UNIT 38 V 40 V 9.7 V VIN UVLO Turn-On Voltage Input Voltage Rising VIN UVLO Hysteresis Input Voltage Falling 1.1 VEN = 3V, VFB = 1V 0.9 VEN = 3V, VOUT = 5V, No load 3.0 VEN = 0V 75 115 µA 808 824 mV Standby Supply Current Shutdown Supply Current Feedback Voltage 9.0 792 Internal Soft-Start Time Error Amplifier Transconductance VFB = VCOMP = 0.8V, ∆ICOMP = ± 10µA Error Amplifier DC Gain Switching Frequency VFB = 0.808V Foldback Switching Frequency VFB = 0V 200 9.4 V 1.4 mA 400 µs 650 µA/V 4000 V/V 225 250 30 Maximum Duty Cycle 85 Minimum On-Time mA kHz kHz 88 91 % 200 ns COMP to Current Limit Transconductance VCOMP = 1.2V 5.25 A/V Secondary Cycle-by-Cycle Current Limit Duty Cycle = 0% 4.5 A Slope Compensation Duty = DMAX 1.2 A 1 V 25000 A/A ISET Voltage ISET to IOUT DC Room Temp Current Gain IOUT / ISET, RISET = 19.6kΩ CC Controller DC Accuracy RISET = 19.6kΩ, VOUT = 3.5V Open-Loop DC Test 1175 1190 1205 mA EN Threshold Voltage EN Pin Rising 1.47 1.6 1.73 V EN Hysteresis EN Pin Falling EN Internal Pull-up Current High-Side Switch ON-Resistance 125 mV 4 µA 0.16 Ω SW Off Leakage Current VEN = VSW = 0V Thermal Shutdown Temperature Temperature Rising 150 °C Thermal Shutdown Temperature Hysteresis Temperature Falling 20 °C Innovative PowerTM -4- 1 10 µA www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 FUNCTIONAL BLOCK DIAGRAM IN AVIN EN BANDGAP, REGULATOR, & SHUTDOWN CONTROL PVIN OSCILLATOR EMI CONTROL Σ PWM CONTROLLER VREF = 0.808V HSB SW VREF = 0.808V FB + CC CONTROL - COMP ISET FUNCTIONAL DESCRIPTION regulating output voltage to regulating output current, and the output voltage will drop with increasing load. CV/CC Loop Regulation As seen in Functional Block Diagram, the ACT4523 is a peak current mode pulse width modulation (PWM) converter with CC and CV control. The converter operates as follows: The Oscillator normally switches at 225kHz. However, if FB voltage is less than 0.6V, then the switching frequency decreases until it reaches a typical value of 30kHz at VFB = 0.15V. A switching cycle starts when the rising edge of the Oscillator clock output causes the High-Side Power Switch to turn on and the Low-Side Power Switch to turn off. With the SW side of the inductor now connected to IN, the inductor current ramps up to store energy in the magnetic field. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higher than the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Oscillator clock output goes low, the High-Side Power Switch turns off. Enable Pin The ACT4523 has an enable input EN for turning the IC on or off. The EN pin contains a precision 1.6V comparator with 125mV hysteresis and a 4µA pull-up current source. The comparator can be used with a resistor divider from VIN to program a startup voltage higher than the normal UVLO value. It can be used with a resistor divider from VOUT to disable charging of a deeply discharged battery, or it can be used with a resistor divider containing a thermistor to provide a temperature-dependent shutoff protection for over temperature battery. The thermistor should be thermally coupled to the battery pack for this usage. At this point, the SW side of the inductor swings to a diode voltage below ground, causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. The High-Side Power Switch is driven by logic using HSB as the positive rail. This pin is charged to VSW + 5V when the Low-Side Power Switch turns on. The COMP voltage is the integration of the error between FB input and the internal 0.808V reference. If FB is lower than the reference voltage, COMP tends to go higher to increase current to the output. Output current will increase until it reaches the CC limit set by the ISET resistor. At this point, the device will transition from Innovative PowerTM If left floating, the EN pin will be pulled up to roughly 5V by the internal 4µA current source. It can be driven from standard logic signals greater than 1.6V, or driven with open-drain logic to provide digital on/off control. Thermal Shutdown The ACT4523 disables switching when its junction temperature exceeds 150°C and resumes when the temperature has dropped by 20°C. -5- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 APPLICATIONS INFORMATION CC Current Line Compensation Output Voltage Setting When operating at constant current mode, the current limit increase slightly with input voltage. For wide input voltage applications, a resistor RC is added to compensate line change and keep output high CC accuracy, as shown in Figure 3. Figure 1: Output Voltage Setting VOUT Figure 3: RFB1 ACT4523 Iutput Line Compensation FB RFB2 Figure 1 shows the connections for setting output voltage. Select the proper ratio of the feedback resistors RFB1 and RFB2 based on output voltage. Typically, use RFB2 ≈ 10kΩ determine RFB1 from the following equation: ⎛ V ⎞ R FB1 = R FB 2 ⎜ OUT − 1 ⎟ 0 . 808 V ⎝ ⎠ the two the and Inductor Selection (1) The inductor maintains a continuous current to the output load. This inductor current has a ripple that is dependent on the inductance value: CC Current Setting ACT4523 constant current value is set by a resistor connected between the ISET pin and GND. The CC output current is linearly proportional to the current flowing out of the ISET pin. The voltage at ISET is roughly 1V and the current gain from ISET to output is roughly 25000 (25mA/1µA). To determine the proper resistor for a desired current, please refer to Figure 2 below. Higher inductance reduces the peak-to-peak ripple current. The trade off for high inductance value is the increase in inductor core size and series resistance, and the reduction in current handling capability. In general, select an inductance value L based on ripple current requirement: L= Figure 2: VOUT × (VIN _VOUT ) VIN fSW ILOADMAX K RIPPLE (2) Curve for Programming Output CC Current where VIN is the input voltage, VOUT is the output voltage, fSW is the switching frequency, ILOADMAX is the maximum load current, and KRIPPLE is the ripple factor. Typically, choose KRIPPLE = 30% to correspond to the peak-to-peak ripple current being 30% of the maximum load current. Output Current vs. RISET ACT4523-002 3500 Output Current (mA) 3000 2500 With a selected inductor value the peak-to-peak inductor current is estimated as: 2000 1500 ILPK _ PK = 1000 VOUT × (VIN _VOUT ) L × VIN × fSW (3) 500 The peak inductor current is estimated as: VIN = 24V, VOUT = 4V 0 8 11 14 17 20 23 26 29 32 1 ILPK = ILOADMAX + ILPK _ PK 2 RISET (kΩ) Innovative PowerTM -6- (4) www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 APPLICATIONS INFORMATION CONT’D The selected inductor should not saturate at ILPK. The maximum output current is calculated as: IOUTMAX = ILIM _ 1 I _ 2 LPK PK Output Capacitor The output capacitor also needs to have low ESR to keep low output voltage ripple. The output ripple voltage is: (5) VRIPPLE = IOUTMAX K RIPPLE RESR + LLIM is the internal current limit, which is typically 3.2A, as shown in Electrical Characteristics Table. VIN 2 28 × fSW LC OUT (6) Where IOUTMAX is the maximum output current, KRIPPLE is the ripple factor, RESR is the ESR of the output capacitor, fSW is the switching frequency, L is the inductor value, and COUT is the output capacitance. In the case of ceramic output capacitors, RESR is very small and does not contribute to the ripple. Therefore, a lower capacitance value can be used for ceramic type. In the case of tantalum or electrolytic capacitors, the ripple is dominated by RESR multiplied by the ripple current. In that case, the output capacitor is chosen to have sufficiently low ESR. External High Voltage Bias Diode It is recommended that an external High Voltage Bias diode be added when the system has a 5V fixed input or the power supply generates a 5V output. This helps improve the efficiency of the regulator. The High Voltage Bias diode can be a low cost one such as IN4148 or BAT54. Figure 4: External High Voltage Bias Diode For ceramic output capacitor, typically choose a capacitance of about 22µF. For tantalum or electrolytic capacitors, choose a capacitor with less than 50mΩ ESR. Rectifier Diode Use a Schottky diode as the rectifier to conduct current when the High-Side Power Switch is off. The Schottky diode must have current rating higher than the maximum output current and a reverse voltage rating higher than the maximum input voltage. This diode is also recommended for high duty cycle operation and high output voltage applications. Input Capacitor The input capacitor needs to be carefully selected to maintain sufficiently low ripple at the supply input of the converter. A low ESR capacitor is highly recommended. Since large current flows in and out of this capacitor during switching, its ESR also affects efficiency. The input capacitance needs to be higher than 10µF. The best choice is the ceramic type, however, low ESR tantalum or electrolytic types may also be used provided that the RMS ripple current rating is higher than 50% of the output current. The input capacitor should be placed close to the IN and G pins of the IC, with the shortest traces possible. In the case of tantalum or electrolytic types, they can be further away if a small parallel 0.1µF ceramic capacitor is placed right next to the IC. Innovative PowerTM -7- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 STABILITY COMPENSATION If RCOMP is limited to 15kΩ, then the actual cross over frequency is 6.58 / (VOUTCOUT). Therefore: Figure 5: Stability Compensation C COMP = 6 . 45 × 10 _ 6 VOUT C OUT (F) (14) STEP 3. If the output capacitor’s ESR is high enough to cause a zero at lower than 4 times the cross over frequency, an additional compensation capacitor CCOMP2 is required. The condition for using CCOMP2 is: R ESRCOUT ≥ (Min c: CCOMP2 is needed only for high ESR output capacitor 0 . 808 V A VEA G COMP I OUT C COMP 2 = G EA 2 π A VEA C The second pole P2 is the output pole: I OUT fP 2 = 2 π V OUT C OUT fZ 1 = And finally, the third pole is due to RCOMP and CCOMP2 (if CCOMP2 is used): fP 3 = 1 (11) 2πR COMP C COMP2 (12) 2 . 83 × 10 R COMP Innovative PowerTM 2.5V 47μF Ceramic CAP 5.6kΩ 3.3nF None 3.3V 47μF Ceramic CAP 6.2kΩ 3.3nF None 5V 47μF Ceramic CAP 8.2kΩ 3.3nF None 2.5V 470μF/6.3V/30mΩ 39kΩ 22nF 47pF 3.3V 470μF/6.3V/30mΩ 45kΩ 22nF 47pF 5V 470μF/6.3V/30mΩ 51kΩ 22nF 47pF To compensate for resistive voltage drop across the charger's output cable, the ACT4523 integrates a simple, user-programmable cable voltage drop compensation using the impedance at the FB pin. Use the curve in Figure 6 to choose the proper feedback resistance values for cable compensation. 5 (F) COUT Output Cable Resistance Compensation STEP 2. Set the zero fZ1 at 1/4 of the cross over frequency. If RCOMP is less than 15kΩ, the equation for CCOMP is: C COMP = RCOMP CCOMP CCOMP2c VOUT The constant-current control loop is internally compensated over the 1500mA-3000mA output range. No additional external compensation is required to stabilize the CC current. 2 π V OUT C OUT f SW 10 G EA G COMP × 0 . 808 V (Ω) (16) CC Loop Stability STEP 1. Set the cross over frequency at 1/10 of the switching frequency via RCOMP: = 5 . 12 × 10 7 VOUT C OUT C OUT R ESRCOUT R COMP c: CCOMP2 is needed for high ESR output capacitor. CCOMP2 ≤ 47pF is recommended. The following steps should be used to compensate the IC: R COMP = (15) Typical Compensation for Different Output Voltages and Output Capacitors (9) (10) 2 π R COMP C COMP (Ω) Table 1: The first zero Z1 is due to RCOMP and CCOMP: 1 ) Table 1 shows some calculated results based on the compensation method above. (8) COMP ,0 . 006 × VOUT Though CCOMP2 is unnecessary when the output capacitor has sufficiently low ESR, a small value CCOMP2 such as 100pF may improve stability against PCB layout parasitic effects. (7) The dominant pole P1 is due to CCOMP: fP 1 = _6 And the proper value for CCOMP2 is: The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 5. The DC loop gain of the system is determined by the following equation: A VDC = 1 . 77 × 10 C OUT (13) -8- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 STABILITY COMPENSATION CONT’D RFB1 is the high side resistor of voltage divider. power GND with vias or short and wide path. In the case of high RFB1 used, the frequency compensation needs to be adjusted correspondingly. As show in Figure 7, adding a capacitor in paralled with RFB1 or increasing the compensation capacitance at COMP pin helps the system stability. 3) Return FB, COMP and ISET to signal GND pin, and connect the signal GND to power GND at a single point for best noise immunity. Connect exposed pad to power ground copper area with copper and vias. 4) Use copper plane for power GND for best heat dissipation and noise immunity. Figure 6: 5) Place feedback resistor close to FB pin. Cable Compensation at Various Resistor Divider Values 6) Use short trace connecting HSB-CHSB-SW loop Delta Output Voltage vs. Output Current Delta Output Voltage (mV) 300 B1 RF = 43 =3 1 R FB 250 R 200 0k 1 FB 60 k k 00 =3 k 40 =2 Figure 8 shows an example of PCB layout. ACT4523-003 350 1 R FB 150 00k =2 0k = 15 R FB1 R FB1 100 RFB1 50 k = 100 k 1 =5 R FB1 0 0 0.4 0.8 1.2 1.6 2 Output Current (A) Figure 7: Frequency Compensation for High RFB1 Figure 8: PCB Layout PC Board Layout Guidance Figure 9 gives one typical car charger application schematic and associated BOM list. When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the IC. 1) Arrange the power components to reduce the AC loop size consisting of CIN, IN pin, SW pin and the schottky diode. 2) Place input decoupling ceramic capacitor CIN as close to IN pin as possible. CIN is connected Innovative PowerTM -9- www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 Figure 9: Typical Application Circuit for 5V/2.1A Car Charger Table 2: BOM List for 5V/2.1A Car Charger ITEM REFERENCE DESCRIPTION MANUFACTURER QTY 1 U1 IC, ACT4523YH, SOP-8EP Active-Semi 1 2 C1 Capacitor, Electrolytic, 47µF/50V, 6.3х7mm Murata, TDK 1 3 C2 Capacitor, Ceramic, 10µF/50V, 1206, SMD Murata, TDK 1 4 C3 Capacitor, Ceramic, 2.2nF/6.3V, 0603, SMD Murata, TDK 1 5 C4 Capacitor, Ceramic, 22nF/50V, 1206, SMD Murata, TDK 1 6 C5 Capacitor, Electrolytic, 220µF/10V, 6.3х7mm Murata, TDK 1 7 C6 Capacitor, Ceramic, 1µF/10V, 0603, SMD Murata, TDK 1 8 L1 Inductor,33µH, 3A, 20%, SMD Tyco Electronics 1 9 D1 Diode, Schottky, 40V/3A, SK34 Diodes 1 10 D2 Diode, 75V/150mA, LL4148 Good-ARK 1 11 R1 Chip Resistor, 11.5kΩ, 0603, 1% Murata, TDK 1 12 R2 Chip Resistor, 52kΩ, 0603, 1% Murata, TDK 1 13 R3 Chip Resistor, 8.2kΩ, 0603, 5% Murata, TDK 1 14 R4 Chip Resistor, 10kΩ, 0603, 1% Murata, TDK 1 Innovative PowerTM - 10 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) Efficiency vs. Load current 90 85 VIN = 24V 80 75 70 65 VOUT = 5V ACT4523-005 ACT4523-004 VIN = 12V 95 Efficiency (%) Switching Frequency vs. Input Voltage 250 Switching Frequency (kHz) 100 230 210 190 170 150 130 110 60 200 600 1000 1400 1800 10 2200 15 20 Load Current (mA) 35 40 2600 CC Current (mA) 210 ACT4523-007 2700 ACT4523-006 Switching Frequency (kHz) 30 CC Current vs. Temperature Switching Frequency vs. Feedback Voltage 260 160 110 2500 2400 2300 2200 60 2100 10 0 100 200 300 400 500 600 700 800 2000 900 25 45 65 CC Current vs. Input Voltage 105 125 Maximum CC Current (A) 2200 2000 1800 1600 ACT4523-009 4.2 ACT4523-008 2400 4.05 3.9 3.75 3.6 3.45 3.3 3.15 3 14 18 22 26 30 34 20 38 30 40 50 60 70 Duty Cycle Input Voltage (V) Innovative PowerTM 145 Maximum Peak Current vs. Duty Cycle 2600 10 85 Temperature (°C) Feedback Voltage (mV) CC Current (mA) 25 Input Voltage (V) - 11 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) Standby Current vs. Input Voltage Shutdown Current vs. Input Voltage 175 3 Standby Supply Current (mA) Shutdown Current (µA) 145 130 115 100 85 70 10 15 20 25 30 35 ACT4523-011 ACT4523-010 160 40 2.5 2 1.5 1 0.5 0 0 4 8 12 20 24 28 32 36 40 Input Voltage (V) Input Voltage (V) Start up into CC mode Reverse Leakage Current (VIN Floating) 120 ACT4523-013 ACT4523-012 160 Reverse Leakage Current (µA) 16 VOUT = 5V RLORD = 1.5Ω IISET = 2A VIN = 12V CH1 80 40 CH2 0 0 1 2 3 4 5 CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 200µs/div VOUT (V) Start up into CC mode ACT4523-015 ACT4523-014 VOUT = 5V RLORD = 1.5Ω IISET = 2A VIN = 24V SW vs. Output Voltage Ripples VIN = 12V VOUT = 5V IOUT = 2.1A CH1 CH1 CH2 CH2 CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 200µs/div Innovative PowerTM CH1: VOUT Ripple, 20mV/div CH2: SW, 5V/div TIME: 2µs/div - 12 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) SW vs. Output Voltage Ripple Start up with EN CH1 ACT4523-017 ACT4523-016 VIN = 24V VOUT = 5V IOUT = 2.1A VIN = 12V VOUT = 5V IOUT = 2.1A CH1 CH2 CH2 CH1: EN, 2V/div CH2: VOUT, 2V/div TIME: 400µs//div CH1: VRIPPLE, 20mV/div CH2: SW, 10V/div TIME: 2µs/div Load Step Waveforms Start up with EN VIN = 12V VOUT = 5V IISET = 2.1A ACT4523-019 VIN = 12V VOUT = 5V IISET = 2.1A ACT4523-021 ACT4523-018 VIN = 24V VOUT = 5V IISET = 2.1A CH1 CH1 CH2 CH2 CH1: EN, 2V/div CH2: VOUT, 2V/div TIME: 400µs//div CH1: VOUT, 200mV/div CH2: IOUT, 1A/div TIME: 200µs//div Short Circuit Load Step Waveforms ACT4523-020 VIN = 24V VOUT = 5V IISET = 2.1A CH1 CH1 CH2 CH2 CH1: VOUT, 200mV/div CH2: IOUT, 1A/div TIME: 200µs//div Innovative PowerTM CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 100µs//div - 13 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 TYPICAL PERFORMANCE CHARACTERISTICS CONT’D (L = 33µH, CIN = 10µF, COUT = 47µF, Ta = 25°C, RCOMP = 8.2k, CCOMP1 = 2.2nF, CCOMP2 = NC) Short Circuit Short Circuit Recovery VIN = 12V VOUT = 5V IISET = 2.1A ACT4523-023 ACT4523-022 VIN = 24V VOUT = 5V IISET = 2.1A CH1 CH1 CH2 CH2 CH1: VOUT, 2V/div CH2: IOUT, 1A/div TIME: 100µs//div CH1: VOUT, 2V/div CH2: IOUT, 2A/div TIME: 1ms/div Short Circuit Recovery ACT4523-024 VIN = 24V VOUT = 5V IISET = 2.1A CH1 CH2 CH1: VOUT, 2V/div CH2: IOUT, 2A/div TIME: 1ms/div Innovative PowerTM - 14 - www.active-semi.com Copyright © 2012 Active-Semi, Inc. ACT4523 Rev 5, 14-Nov-12 PACKAGE OUTLINE SOP-8EP PACKAGE OUTLINE AND DIMENSIONS SYMBOL DIMENSION IN MILLIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 1.350 1.700 0.053 0.067 A1 0.000 0.100 0.000 0.004 A2 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 c 0.170 0.250 0.007 0.010 D 4.700 5.100 0.185 0.200 D1 3.202 3.402 0.126 0.134 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 E2 2.313 2.513 0.091 0.099 e 1.270 TYP 0.050 TYP L 0.400 1.270 0.016 0.050 θ 0° 8° 0° 8° Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact [email protected] or visit http://www.active-semi.com. is a registered trademark of Active-Semi. Innovative PowerTM - 15 - www.active-semi.com Copyright © 2012 Active-Semi, Inc.